Membrane fouling and its control in drinking water membrane filtration process
Notice bibliographique
Résumé
Treatment of surface water in the presence of natural organic matters (NOM) becomes a challenging issue to meet stringent rules of Safe Drinking Water Act (SDWA). Ultrafiltration (UF) membrane is emerging as an efficient technology for the purpose of potable water production. However, membrane fouling, ageing and chemical cleaning affect its performance and properties. \nThe effects of ageing and chemical cleaning on performance and properties of the membrane were studied using UF membrane from full scale drinking water membrane filtration plant and simulated chemical cleaning sequences in laboratory. Organic and inorganic foulants, and membrane properties such as tensile strength, membrane morphology and surface functional groups were characterized using various analytical tools. The results from simulated chemical cleaning experiments were consistent with those from a full-scale plant, in terms of the effects of chemical cleaning on membrane properties. The results show that membrane ageing deteriorated the tensile strength and membrane integrity, and led to accumulation of foulants. Hypochlorite cleaning resulted in a decrease in membrane tensile strength, while citric acid cleaning had limited effect on membrane tensile strength. The decrease in membrane tensile strength correlated to a decrease in intensity of functional groups measured by FTIR. The results suggest that hypochlorite concentration and cleaning time should be minimized to reduce their impacts on membrane properties. \nAdditionally, membrane cleaning strategies (cleaning agents? concentration, cleaning time, pH, backwash frequency, and production time) currently used in Bare Point Water Treatment Plant were studied using a ZW-1000 pilot scale plant. The membrane performance in terms of permeability recovery was assessed using the recorded data; and organic and inorganic foulants were analyzed using Total Organic Carbon analyser (TOC) and Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES). In sodium hypochlorite (NaClO) cleaning, lower concentrations combined with longer soak time achieved higher permeability recovery, with TOC results indicating that the major foulants responsible for permeability decrease were organic. Similarly, the results of citric acid cleaning suggest that lower pH was more effective in permeability recovery. \nFurthermore, the effect of production cycle or backwash frequency on the membrane performance was also studied to optimize water recovery; the results revealed that the membrane performances, fouling rate in terms of rate of change of TMP, recovery (%), and organic fouling depended on permeate cycle length or back wash frequency. This research concludes with the hypothesis that membrane fouling and ageing deteriorate membrane performance, whereas chemical cleaning agent (NaClO) enhances membrane performance and properties, respectively.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,003 | 0,005 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,001 |
| Bibliométrie | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,002 | 0,001 |
| Communication savante | 0,003 | 0,002 |
| Science ouverte | 0,001 | 0,001 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».